i2c: i801: Improve status polling

Polling uses the same timeout as irq mode: 400 * 500us = 200ms = HZ / 5.
So let's use the adapter->timeout value also for polling. This has the
advantage that userspace can control the timeout value for polling as
well. In addition change the code to make it better readable.
Last but not least remove the timeout debug messages. Calls to both
functions are followed by a call to i801_check_post() that will print
an error message in case of timeout.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Tested-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Wolfram Sang <wsa@kernel.org>